Criminal and psychological experts say they’d be surprised if investigators didn’t find evidence of psychological problems in either of the 12-year-old Wisconsin girls who allegedly tried to stab their friend to death over the weekend.

The girls told police they attacked their friend in the woods to please an internet meme called Slender Man, a fictional character who hunts children and has no face, according to the Associated Press.

The girls thought if they killed their friend, Slender Man would reveal himself, and they could prove he was real, according to the Milwaukee Journal-Sentinel.

Abe Van Dyke/AP

Rescue workers take a 12-year-old stabbing victim to an ambulance in Waukesha, Wis. after she was attacked by two 12-year-old-friends who claim they were inspired by a story they read online.

Dominick Diorio, 40, of Old Bethpage, New York, has been charged with third-degree assault as a hate crime, assault, harassment and aggravated harassment in connection with the incident involving Stiviano outside the Gansevoort Hotel, New York police said Tuesday.